Key result
Maximum breathing increased cerebral and peripheral blood flow, voluntary hyperventilation decreased cerebral flow, and the Valsalva maneuver decreased both flows.
Why the study?
How do maximum breathing, voluntary hyperventilation, and the Valsalva maneuver affect cerebral and peripheral hemodynamics in healthy males?
Observational (n=8)
How do maximum breathing, voluntary hyperventilation, and the Valsalva maneuver affect cerebral and peripheral hemodynamics in healthy males?
Different respiratory maneuvers elicit distinct, immediate physiological changes in cerebral and peripheral blood flow, blood pressure, and heart rate.
Respiratory maneuvers may alter cerebral and peripheral hemodynamics; leaves open clinical relevance and need for validation in larger patient cohorts.
Circulatory effects of three kinds of respiratory maneuvers (maximum breathing, voluntary hyperventilation and the Valsalva maneuver) on cerebral hemodynamics (blood flow in the internal carotid artery) and periphral hemodynamics (blood flow in the brachial artery) were examined in 4 normal young males and 4 healthy looking elderly males by means of a newly devised ultrasonic Doppler apparatus, which is capable of multiple and simultaneous blood flow measurement non-operatively and continuously in man in situ. Further, blood pressure, heart rate and arterial gas contents (PO2 PCO2, pH) were simultaneously investigated. The following results were obtained. (1) Maximum breathing Cerebral and peripheral blood flow were increased and the changing rate of the former was more conspicuous than the latter. Blood pressure and heart rate were increased and arterial gas contents showed respiratory alkalosis. (2) Voluntary hyperventilation Cerebral blood flow was decreased but no alteration of peripheral blood flow was found. Cerebral blood flow reached the minimum level immediately after the onset of the maneuver (about I to 2 minutes). The change of cerebral blood flow during the maneuver was divided into the following two types. Type I - cerebral blood flow was maintained at the same level during the maneuver and Type 2 - cerebral blood flow returned to the control level during the maneuver. The former type was more frequent than the latter, i.e., 6 : 2 cases. The changes of blood pressure and heart rate were slight and arterial gas contents showed respiratory alkalosis. (3) Valsalva maneuver Cerebral and peripheral blood flow was decreased. Although peripheral blood flow returned to the control level, cerebral blood flow showed a transient but conspicuous increase immediately after the maneuver. Blood pressure was decreased and heart rate was increased. Arterial gas contents generally showed respiratory alkalosis. (4) Based on the results, the pathophysiology and clinical significance of each maneuver were discussed.
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Manabu Miyazaki (1973) conducted an observational in Healthy (n=8). Respiratory maneuvers (maximum breathing, voluntary hyperventilation, Valsalva maneuver) vs. Baseline was evaluated on Cerebral hemodynamics (blood flow in the internal carotid artery) and peripheral hemodynamics (blood flow in the brachial artery). Maximum breathing increased cerebral and peripheral blood flow, voluntary hyperventilation decreased cerebral flow, and the Valsalva maneuver decreased both flows.
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